1. Field of the Invention
The present invention relates to a flying type magnetic head employed in a magnetic disk apparatus.
2. Discussion of Background
It is required of a flying type magnetic head employed in a magnetic disk apparatus in recent years that, in order to achieve high density recording/reproduction, the flying height at the electromagnetic conversion elements be reduced to, for instance, 20nm or less. In addition, magnetic heads that employ magnetoresistive elements (hereafter referred to as MR elements) capable of achieving high reproduction output without being dependent upon the relative speed between the magnetic disk and the magnetic head as their reproduction element have been put into practical use.
With this type of magnetic head, since it operates at an extremely small flying height, it is inevitable that it will at times come in contact with minute irregularities at the surface of the magnetic disk.
In a magnetic head employing an MR element for reproduction, noise is generated at the MR element when the magnetic head touches the minute irregularities at the surface of the magnetic disk due to the heat generated by the contact. This type of noise is referred to as thermal asperity (hereafter referred to as TA) noise among persons skilled in the field.
As a means for preventing TA noise, Japanese Unexamined Patent Publication (KOKAI) No. 287444/1996 discloses a technology whereby the MR element is made to operate at a distance from the air bearing surface (hereafter referred to as ABS). Apart from this, means for correcting TA noise by an electrical circuit and the like are also known.
However, if the MR element is made to operate at a distance from the ABS, a reduction in the reproduction sensitivity of the MR element will result. In addition, even if a method of compensating for the TA noise through an electrical circuit is employed, it is technically difficult to compensate for all TA noise through such a circuit.
In order to avoid the generation of TA noise, the flying height of the magnetic head must be set large to ensure that the magnetic head does not come in contact with the minute irregularities on the magnetic disk, which makes it impossible to respond to the need for high density recording that may be achieved through lower flying height.